The KEF Ci5120QLM-THX is a premium THX® Certified Ultra in-wall speaker engineered for large-room home theater performance. Its 12th generation Uni-Q® array and MAT™ deliver wide dispersion, sharper imaging, and cleaner detail for movies and music. Four long-throw bass drivers produce deep, controlled low end while maintaining low distortion at high output. With a paintable magnetic grille and Ultra-Thin Bezel styling, it disappears into the wall while your sound takes over the room. Key Features List (6 Succinct Bullets)
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KEF Ci5120QLM-THX In-Wall Speaker

The KEF Ci5120QLM-THX is a high-performance THX® Certified Ultra in-wall speaker designed to deliver true cinema-scale sound in large rooms—without visible floor-standing speakers. Built around KEF’s 12th generation Uni-Q® driver array and Metamaterial Absorption Technology (MAT™), it produces exceptionally clear dialogue, precise imaging, and controlled detail even at high volume. A powerful 3-way architecture with four long-throw bass drivers delivers deep, clean low end while keeping distortion low, making it ideal for premium home theater, media rooms, and multipurpose living spaces. Finished with a paintable magnetic metal grille and Ultra-Thin Bezel (UTB) styling, it blends seamlessly into the wall while your soundtrack takes center stage.

What It’s Good At:

• Delivering THX Certified Ultra home-theater impact for large rooms with reference-style dynamics
• Creating a wide listening area thanks to Uni-Q point-source dispersion and 150° nominal coverage
• Producing cleaner, more accurate mids/highs by absorbing unwanted rear energy with MAT™
• Hitting tight, low-distortion bass using four 120mm long-throw LF drivers
• Installing cleanly with an architectural look via Ultra-Thin Bezel and paintable magnetic grille
• Supporting high-output systems with robust power handling and 25–250W recommended amplifier power

KEF Ci5120QLM-THX Full Specifications:

• Model: Ci5120QLM-THX
• Series: Q Series
• THX Certification: THX® Certified Ultra
• Frequency Response Range: 45Hz – 20kHz
• Frequency Response Remark: (±6dB) open-backed
• Frequency Range: 38Hz – 20kHz
• Sensitivity: 89dB
• Nominal Impedance: 4Ω
• Nominal Coverage: 150°
• Maximum SPL: 105dB
• Drive Units:
  • LF: 4 × 120mm (4.75 in.)
  • MF: 100mm (4 in.) Uni-Q
  • HF: 19mm (0.75 in.) vented aluminium dome with Metamaterial Absorption Technology¹
• Crossover Frequency: 440Hz, 2.75kHz
• Recommended Amplifier Power: 25 – 250 W
• Recommended High-Pass Filter (Hz): 35Hz – 100Hz
• Product External Dimensions (H × W × D): 818mm × 186mm × 96mm (32.2in. × 7.3in. × 3.8in.)
• Cut-Out Dimensions (H × W): 795mm × 163mm (31.3in. × 6.4in.)
• Mounting Depth From Surface: 90mm (3.6")
• Mounting Thickness:
  • Maximum: 36mm (1.42in.)
  • Minimum: 6mm (0.24in.)
• Ideal Rear Volume (L): 70
• Minimum Rear Volume (L): 35
• Net Weight: 9.7KG (21.4 lbs.)
• Gross Weight:
  • Single box: 12.8KG (28.2 lbs.)
  • Master box: 27KG (59.5 lbs.)
• Safety And Regulatory Compliance: IP64
• Remarks: ¹ Metamaterial Absorption Technology is a joint development with Acoustic Metamaterials Group.

KEF Ci5120QLM-THX Q&A:

How is the KEF Ci5120QLM-THX installed in the wall?

Install using the included cutout template to mark the opening, run speaker wire to the location, connect wiring, and secure the speaker per the manual. If you’re not comfortable cutting drywall or working around studs/wiring, professional installation is recommended for best results.

Are in-wall speakers a good choice compared to traditional box speakers?

In-wall speakers can deliver excellent sound while saving space and reducing visual clutter. The tradeoff is reduced placement flexibility after installation, so planning layout and listening positions is important.

What makes the Ci5120QLM-THX a strong option for home theater?

It combines THX® Certified Ultra performance with Uni-Q® dispersion and MAT™ for clearer, more immersive sound. The 3-way design and four bass drivers help deliver impactful dynamics and clean low end in larger rooms.

What amplifier power is recommended for this speaker?

KEF recommends 25–250W of amplifier power, giving you flexibility from moderate systems to high-performance home-theater amps.

Does this speaker need a high-pass filter or a subwoofer crossover setting?

A recommended high-pass filter range of 35Hz–100Hz is provided, allowing you to integrate the speaker smoothly with subwoofers based on your room size and bass goals.

How much wall depth is needed to mount it properly?

The mounting depth from the surface is 90mm (3.6"), with external depth listed as 96mm (3.8in.). Confirm stud bay depth and any obstructions before cutting.

What rear volume does the Ci5120QLM-THX require?

For optimal performance, the ideal rear volume is 70 L, with a minimum of 35 L. Proper rear volume helps the speaker deliver consistent bass and overall balance.

Can the grille be painted to match the wall?

Yes. It includes a paintable magnetic metal grille and an Ultra-Thin Bezel (UTB) design for a clean, built-in look.

KEF Ci5120QLM-THX Downloads:

KEF Ci5120QLM-THX Manual
KEF Ci5120QLM-THX Specifications Sheet
KEF Ci5120QLM-THX Drawing